Sound box of talking machines



.1. DURHAM SOUND BOX VO1 TALKING MACHINES Jan. 12 1926;

Filed April 17, 1923 11115121311, lis.;

s. Illy 17V VEA/T077:

Patented Jan. 12, 1926.

UNITED STATES JOSEPH DURHAM, OF SYDNEY, NEW SOUTH WALES, AUSTRALIA.

SOUND Boxv or TALKING MACHINES.

Applcationled April 17, 1923. Serial No. 632,646.

To all whom may concern.'

Be it known that I, JOSEPH DURHAM, a subject of the King of Great Britain, residing at Sydney, in the State of New South Wales, Commonwealth of Australia, have invented new and useful Improvements in and Connected with the Sound Boxes of rlialkincr Machines, of which the following is a specification.

This invention relates to improvements in and connected with the sound-boxes of talking machines.

It is an object of the invention to provide improvements whereby the sound-box and its movable back or retaining cap-plate can be conveniently assembled and maintained in Arequired position in such a manner that,

merely by the operation of screwing up the retaining cap-plate in the usual manner, the sound-box is rendered sound-insulated.

A further object of the invention is to provide means that will preclude the transmission by the stylus to the sound-box and tone arm of a talking machine of any extraneous sounds, or vibrations other than those produced under the action of the stylus in following the phonographic sound line.

Vith these and other objects in view the invention consists of the features of construction, combination and arrangement hereinafter fully described, reference beingl had to the accompanying drawings wherein Figure 1 is a general view of a sound-box and associated integers of a talking machine, and

Figure 2 is a sectional view of 'the same.

The sound-box casing 1 is constructed from suitable metal and provided with the usual circular aperture 2, and it is detachably mounted in a clamping ring 3 having a removable retaining cap-plate 4, to which is attached the socket for its convenient connection with the swinging tone arm of a talking machine. The retaining cap-plate 4 is conveniently secured to said clamping ring 8 by the screws 5, which are in threaded engagement with said ring, and have their heads preferably countersunk into the interior surface of said plate;

The sound-box casing 1 provides a seat for the gasket 6 which forms the mounting for the diaphragm 7 by impi'nging upon the opposite marginal faces of the diaphragm.

The clamping ring 3 has its interior surface 8 inclined or undercut, while the sound- Vbox casing 1 has the interior surface 9 correspondingly inclined, whereby two opposed inclined surfaces are presented. Between these opposed inclined surfaces there is interposed a sound insulating ring 10 of rubber or such suitable packing and non-resonant material.

A sound insulating disc 11 of rubber or like suitable material is also inserted between the retaining cap-plate 4 and the sound-box, while the usual stop pin 12,-

which prevents independent rotatable movement of the sound-box casing 1 and retainl ing cap-plate 4 (when assembled) has an insulating sleeve 13, preferably of rubber or like compressible material. v

It will be understood that when the sound box casing 1, the clamping ring 3, and capplate 4 are in position for assembly, the tightening of the fastening screws 5 draws the opposed inclined surfaces 8 and 9 towards each other in Wedge fashion, producing compressional force on the sound insulating members 10, 11 and 13 such as will obviate all possibility of slip thereof and tendency to detachment of the assembled integers. The action of tightening said fastening screws 5 effects thorough insulation of the sound-box, which insulation has in practice been found to be very advantageous, for the reason that it entirely eliminates the transmission by the stylus 14, stylus holder 15, and stylus bar 16 to the sound-box and tone arm of any extraneous sounds, or vibrations other than those produced under the action of the stylus following the phonographic sound line of the record. Furthermore, better reproduction results will be obtained when there are being used records of imperfect nature, or records which have a tendency to blast, due to the resiliency of connection between the sound-box casing and its retaining cap-plate.

Modifications in constructional details, in design and in arrangement may be made within the ambit of the invention as defined by the following claiming clauses.

That I claim is 1. A sound box for talking machines, comprising a clamping ring having an inclined yinner surface, a diaphragm carrying casing fitted within said clamping ring and having an inclined outer surface, a packing ring of sound insulating and non-resonant material fitted between the inclined surfaces of the casing and ring, a stylus bar, a stylus holder and a retaining cap plate substantially as described.

- 2. A sound boi; for talking machines comprising a Clamping ring having an inclined surface, a diaphragm carrying casing fitted within said clamping ring and having an inclined outer surface, a packing ring of sound insulating and non-resonant material 10 titted between the inclined surfaces of the ring and casing, a stylus bar, a stylusholder, a retaining cap secured to said clamping ring, and a packing disk of sound insulating and non-resonant material interposed between the said retaining cap plate and the clamping ring and casing substantially as described.

In testimony whereof I affix my signature.

JOSEPH DURHAM. 

